The derivative of $x^{2}$ is $2x$. For the term $xy$, we use the product rule, which gives us $y + x\frac{dy}{dx}$. The derivative of $-y^{2}$ is $-2y\frac{dy}{dx}$. The derivative of the constant $4$ is $0$. So, we have:
$$2x + y + x\frac{dy}{dx} -
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